Multi-temperature evaporator refrigerator system with variable speed compressor

Abstract

A refrigeration appliance is provided having at least two refrigeration compartments, each compartment having its own access door. The appliance includes a single evaporator located in a plenum which is selectively in communication with each of the compartments, a single compressor, preferably run by a variable speed motor, and a refrigerant circuit including a series of conduits for providing a flow of refrigerant to the evaporator and compressor. A first restriction device is provided in the conduit connecting the compressor with the evaporator, the restriction device operating at a first pressure level. A second restriction device is also provided in the conduit connecting the compressor with the evaporator, preferably in parallel with the first restriction device, the second restriction device operating at a pressure level higher than the first pressure level. Also, a valve or valves preferably of the latching kind, is positioned in the refrigerant circuit for directing refrigerant to a selected one of the restriction devices, or closing both circuits entirely. A phase change material may be used in the refrigeration circuit, downstream of the restriction devices to improve energy efficiency of the system. Also, with this system, the compartments of the refrigerator appliance can be run either in freezer or in fresh food cooling mode as desired, providing convertible refrigerating compartments.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
       1. A refrigeration appliance having at least two refrigeration compartments, each compartment having its own access door, comprising: a single evaporator located in a plenum which is in communication with each of said compartments;   a single compressor;   a refrigerant circuit comprising a series of conduits for providing a flow of refrigerant to said evaporator and compressor; and   a first restriction device in said conduit connecting said compressor with said evaporator, said restriction device operating at a first pressure level;   a second restriction device in said conduit connecting said compressor with said evaporator, said second restriction device operating at a pressure level higher than said first pressure level; and   valve means in said refrigerant circuit for directing refrigerant to a selected one of said restriction devices.   
     
     
       2. A refrigeration appliance according to claim 1, further including means for selectively opening and closing communication between said plenum and each of said compartments. 
     
     
       3. A refrigeration appliance according to claim 2, wherein said means for selectively opening and closing comprises baffles which open communication between said plenum and one of said compartments when they close communication with each of said other compartments. 
     
     
       4. A refrigeration appliance according to claim 1, further including a phase change material positioned downstream of said restriction devices in said refrigeration circuit. 
     
     
       5. A refrigeration appliance according to claim 1, wherein said first compartment is maintained at a temperature below 0° centigrade. 
     
     
       6. A refrigeration appliance according to claim 1, wherein said second compartment is maintained at a temperature above 0° centigrade. 
     
     
       7. A refrigeration appliance according to claim 1, wherein said compressor is driven by a multiple speed motor. 
     
     
       8. A refrigeration appliance according to claim 7, wherein said multiple speed motor is a variable speed motor. 
     
     
       9. A refrigeration appliance according to claim 1, including an air moving device in said plenum for circulating air from said compartments over said evaporator. 
     
     
       10. A refrigeration appliance according to claim 9, wherein said air moving device is powered by an adjustable speed motor. 
     
     
       11. A refrigeration appliance according to claim 1, wherein said first restriction device is a capillary tube. 
     
     
       12. A refrigeration appliance according to claim 1, wherein said second restriction device is a capillary tube. 
     
     
       13. A refrigeration appliance according to claim 1, wherein said second restriction device is connected in parallel with said first restriction device between said compressor and said evaporator. 
     
     
       14. A refrigeration appliance according to claim 1, wherein said valve means comprises a three-position latching valve positioned between said compressor and said first and second restriction devices. 
     
     
       15. A refrigeration appliance according to claim 1, wherein said valve means comprises a two-position latching valve positioned between said compressor and said second restriction device. 
     
     
       16. A refrigeration appliance according to claim 15, further including a second two-position latching valve positioned between said compressor and said first restriction device. 
     
     
       17. A refrigeration appliance according to claim 2, including control means for said opening and closing means to permit selection of either of said compartments to communicate with said plenum when either of said restriction devices is being utilized. 
     
     
       18. A refrigeration appliance having at least two refrigeration compartments, each compartment having its own access door, comprising: a single evaporator located in a plenum communicating with each of said compartments;   a single condenser;   a single compressor;   a refrigerant circuit comprising a series of conduits for providing a flow of refrigerant to said evaporator, said condenser and compressor; and   a first restriction device in said conduit between said condenser and said evaporator, said first restriction device operating at a first pressure level to maintain   said first compartment at a temperature below 0° centigrade;   a second restriction device in said conduit between said condenser and said evaporator, said second restriction device operating at a pressure level higher than said first pressure level to maintain said second compartment at a temperature above 0° centigrade;   valve means in said refrigerant circuit for directing refrigerant to a selected one of said restriction devices from said condenser; and   means for selectively opening and closing communication between said plenum and each of said compartments.   
     
     
       19. A refrigeration appliance according to claim 18, wherein said means for selectively opening and closing comprises movable baffles which open communication between said plenum and one of said compartments when then close communication with each of said other compartments. 
     
     
       20. A refrigeration appliance according to claim 18, wherein further including a phase change material positioned downstream of said restriction devices in said refrigeration circuit. 
     
     
       21. A refrigeration appliance according to claim 18, wherein said compressor is driven by a variable speed motor. 
     
     
       22. A refrigeration appliance according to claim 18, including an air moving device in said plenum for circulating air from said compartments over said evaporator. 
     
     
       23. A refrigeration appliance according to claim 22, wherein said air moving device is powered by an adjustable speed motor. 
     
     
       24. A refrigeration appliance according to claim 18, wherein said first and second restriction devices are each a capillary tube. 
     
     
       25. A refrigeration appliance according to claim 18, wherein said second restriction device is connected in parallel with said first restriction device between said condenser and said evaporator. 
     
     
       26. A refrigeration appliance according to claim 18, wherein said valve means comprises a three-position latching valve positioned between said condenser and said first and second restriction device. 
     
     
       27. A refrigeration appliance according to claim 18, wherein said valve means comprises a two-position latching valve positioned between said compressor and said second restriction device. 
     
     
       28. A refrigeration appliance according to claim 27, further including a second two-position latching valve positioned between said compressor and said first restriction device. 
     
     
       29. A refrigeration appliance according to claim 18, including control means for said opening and closing means to permit selection of either of said compartments to communicate with said plenum when either of said restriction devices is being utilized.